Heat treatment is indispensable in fish canning to provide an acceptable shelf life. Its optimisation reduces the risk of the presence of Clostridium botulinum spores, which could potentially cause botulism cases. This study evaluated canned fish samples for botulism neurotoxin (BoNT)-producing clostridia contamination and can bulging through microbiological contaminant growth. A new analytical approach was developed for detection of such clostridia and phenotypically similar species.

The aim of the study was to present cases of botulism in animals found in Poland in 2019–2021. The analytical laboratory diagnosis and difficulties that occurred in the interpretation of the results are described.